In the episode "An Origin Story" Walter, Peter and Olivia try to attack the future using one of the Portals they opened to transfer stuff in the past. Now Walter assumes that the attack they performed would create havok for years but then are baffled that a new portal was opened almost instantly. In the question found here it is explained why their attack "failed" which is the solution I personally gave to why it failed. My question is
-How could Walter, with the amazing mind he possesses could be baffled by something with such a simple explanation? Let's their attack was so devastating that it took 2000 years to resolve. After fixing everything they could again send something in the same time and space as they were originally planning thus the new instantaneous portal.